The aim of this research is to develop an oviduct-specific expression vector for the ultimate goal of producing pharmaceutical proteins in eggs of transgenic chickens generated by embryonic stem (ES) cell-mediated transgenesis technology. Regulatory sequences from the Ovalbumin (Ov) gene will be isolated from a chicken genomic library. Expression vectors with Ov regulatory sequences will be constructed and tested in primary tubular gland cells from the chicken oviduct. Also explored is a strategy for quick substitution of the protein to be produced in the expression vector. The expression vectors will be introduced into chicken ES cells to produce chimeras which will be bred to obtain germline transmission in the Phase II study. The expression vector developed in this study in conjunction with Origen's ES cell technology will greatly improve the existing transgenic chicken expression systems. The end point of this research is a truly tissue-specific and yet high yield expression system that facilitates production of new pharmaceutical proteins. The system is scalable, rapid and will produce proteins with minimum expense. PROPOSED COMMERCIAL APPLICATION: This technology can be widely applied to large-scale protein production for therapeutic use. The protein can be specifically expressed in the oviduct and deposited into egg white. Large quantity of proteins can be easily purified from egg white. The cloning strategy employed by this system allows production of newly identified therapeutic protein such as monoclonal antibodies in a timely fashion.